Delivery mechanism for printing machines



May 12, 1925. I l1,537,594 T. ELSWCRTH 'ET AL DELIVERY MECHANISM PRINTING MACHINES Filed Sept. l14, 19123 p fhgsb. Hm I A RWM?! LV2- Patented May 12, 1925.

UNITED STATES PATENT OFFICE.

THOR/IAS FRANK ELSVORTH, FEED .WESLEY vl'lGHT, AND PERCY HARKER, OFLEEDS,

ENGLAND, ASSIGNGE-.S OF ONE-FOURTH T0 GEORGE IVIANN AND COMPANY, LIM- ITED, OF LEEDS, YORK, ENGLAND.

DELIVERY MECHANISVI FOR PRINTING MACHINES.

Application e September 14, 1923.

T 0 aZZ whom t may conce/m:

Be it known that we, THOMAS FRANK ELswoR'rH, FRED WESLEY VRIGHT, and Pnecr Hannan, all subjects of the King of Great Britain and ireland, and all residing at Larchield lworks, Hunslet, Leeds,in the county of York, England, have invented certain new and useful improvements in and Relating to Delivery Mechanisms for Printing Machines, of which theL following is a specification.

This invention relates to variable-speed sheet delivery mechanisms for printing machines of the kind wherein the printed sheets are delivered through the medium of continuously or intermittently travelling takeoff chains or the like fitted with two or more sets of grippers each of which in turn receives a printed sheet from the grippers of the continuously rotating printing cylinder or other part of the machine for deposit on a delivery board.

In order to prevent damage to the sheets by coming in contact at too high a speed with the front stops of the delivery board, it has been customary hitherto to slow down the chains at the moment of delivery, with the result that the cyclic length of the chains, i. e. their total travel during a printing cycle has been less than the cyclic peripheral travel of the printing or take-off cylinder, the sheets being thereby deposited on the delivery board in closer proximity to the machine than desirable, with a resulting loss of accessibility.

rThe primary object of the present invention is to overcome this difficulty while other objects are pointed out below.

Referring to the accompanying drawings, which are throughout of a diagrammatic nature Figure l shows an end view of so much of a printing machine as is necessary to eX` plain one form of the present invention,

Figure 2 being a corresponding view taken on the line A-B of Figure l.

In carrying the invention into effect ac cording to the illustrative form shown in the drawings applied by way of example to a rotary printing machine, a differential gear mechanism is arranged at a suitable point in the train of gears through which the chains a are normally driven. The dif- Serial No. 662,756J

ferential pinions b, b gear on the one hand with the driving member, o, which takes the form of an internal toothed wheel loosely mounted on the shaft d and driven by the blanket cylinder e., for example through the medium of gears g and Z secured to spindle .p and on the other hand with the driven member f which takes the form of an ordinary spur gear, keyed to the spindle d which also carries in rigid relation the spur wheel h serving by way of the intermeshing wheel, i, to transmit the desired motion to the chain wheel A rocker le carrying the differential pinionsl Z), Zi is freely mounted upon the common spindle 0l of the driving and driven members and connected by a suitable link m with a double lever n carrying a'runner 0 at one end engaging with the groove 7' of a cam s which is rotated at a uniform speed and in definite timed relation with the machine, for example, by gearing t t from the spindle of the impression cylinder u.

The feed board is indicated at o, and the falling delivery board at w.

The cam groove is so formed that the following action takes place vWith the runner, o, in engagement with a certain concentric part-of the groove the rocker 7c carrying the dilferential pinions L, Y) has no rotation aboutrits axis and the chains are the-n driven at normal speed, i. e. the peripheral speed of the impression cylinder u, the differential member being locked by the cam. The chainV grippers seize the sheet at a convenientv point after the runner has engaged the concentric partiofthe cam groove referred to, which is of suitable length to maintain the differential member locked until the sheet to be delivered is clear, or nearly so, of the impression or take-off cylinder u. The runner now engages with an eccentric part of the cam groove which causes the rocker to move about its axis in a direction to increase the speed of the chains. Subsequently, the runner engages with a further portion of the cam groove which is likewise eccentric, so that the rocker is moved in the reverse direction, thereby reducing the speed of the chains below the normal.

In the class of machine referred to in the above description the sheets may be taken from Vgrippers on the printing or take-oilcylinder or from an appropriate intermediary. v

By suitable design of the cam groove and differential motion, the variations iny speed of the chains may be adapted to particular requirements in accordance with the present invention, so long as at some pointthe speed of the Ychain exceeds the peripheral speed of the take-oil' cylinder. rlhus, in each cyclic movement of vthe chains, during a fraction of their travel, the speed is equal to the normal, while for the remainder of the tra-vel, the speed is partly above and partly below the normal in any desired proportion. In order to gain length of travel as compared with existing machines in which the average speedof the chain is less than the normal, the design of the Vspeed varying mechanism described should be such that the average speed of the chains is equal to or greater than the normal but in particular cases, e. g., when fitted to old machines, the design may be readily varied to give an average speed less than the normal, so that the mechanism can be designed to give cyclic lengths of chain equal to, greater than or less than the cyclic peripheral travel of the printing or take-off cylinder.

` The mechanism described may be moditied in such a manner that the normal speed A of the chains is obtained by the action of they runner in a part of the cam groove which is not concentric in conjunction with the differential pinions.

In general it is not desirable to employ more than two sets of grippers on the delivery chains owing to their weight and the added difficulties of adjustment and it is in such a case that the advantages of the present invention are most marked as regards increased accessibility due to additional length of travel.

The above detailed description is given' anisms, all of which we intend tol include within the scope of this invention.

Having now described our invention, what we claim as new and desire to secure by Letters Patent is Y A printing machine, having in combination an impression cylinder and means for continuously'rotating said cylinder at a substantially uniform speed; delivery chains receiving a sheet direct and a single gear train driving said chains throughout the working cycle, said train including a variable speed gear; together with means for operating said variable speed gear at an appropriate moment to increase the speed of said chains above the uniform peripheral speed of said impression cylinder, as set forth. i

2. A printing machine, having in combination an impression cylinder and means for continuously rotating said cylinder at a substantially uniorm speed; `delivery chains receiving a sheet direct and a single gear train driving said chains throughout the working cycle, said train including a variable speed gear; together with means for operating said variable speed gear at an appropriate moment to increase the speed et" said chains above the uniform peripheral speed of said impression cylinder, and subsequently to siow down said chains to deposit a sheet, as set forth.y I

3. A printing machine as claimed in claim l, in which said variable speed gear and vmeans tor operating said gear comprise a dierential gear train and a timed cam, as set forth.

t. A printing machine as claimed in cla-im l, in which said variable speed gear comprises a differential gear train having pinions and a rocker carrying said pinions while the means for operating said variable speed gear' comprise a timed cam and a lever connected to said rocker, substantially as described.

ln testimony whereof we have signed our names to this specication.

THOMAS FRANK ELSWVORTH. FRED WESLEY WRIGHT. PERCY HARKER. 

